Help - Boring out 308 Liners - Engine Rebuild? | FerrariChat
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Help - Boring out 308 Liners - Engine Rebuild?

Discussion in 'Technical Q&A' started by tomoshea, Jun 7, 2005.

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  1. tomoshea

    tomoshea Formula Junior

    Dec 29, 2003
    541
    Ireland
    Full Name:
    Tom O'Shea
    #1 tomoshea, Jun 7, 2005
    OK,

    I have stripped out my 308 engine, separated major components and I am about to break down the block into its components.

    I have noticed that I can see the top piston ring around the circumference of cylinder 4 (with the piston at BDC) - which leads me to believe that I might have a wear issue, as I believe the tollerence between cylinder and liner is suppossed to .03 - .05. - with that I should not be able to see the piston ring I would have thought?

    I still have to measure ovality in the liners and dimensions of pistons.

    As you cannot get stock pistons any more I may need to bore out the liners and put in place oversize pistons.

    has anyone bored the stock liners on a 308 with the liners in the block.

    I have conflicting advice - one says you can do this - no special tools required,

    Others say you need a plate to fit over the liners to press down against the top of the liners to provent them turning?

    Third says you need to take out all the liners to do this (seems overkill to me)

    Which is right?,

    The car is 26 years old and the liners have never been out, I needed a special head removal tool to get the cylinder heads off, due to alimuminium oxide corrossion between the heads and the block studs.

    Given this is the case is it likely that the corrosion also exists between the liners and the block?

    I would have thought that the liners would have great difficulty in turning given that they are a compression fit into the sleeve?

    If I am right I would have thought that you could just bore the liners out in place with no special tooling.

    Anyone got any experience/ advice or someone I can mail on this?
     
  2. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
    5,379
    NWA
    Full Name:
    Paul
    #2 Artvonne, Jun 7, 2005
    Yes, there are some conflicting viewpoints on these engines, but in the end most everyone agrees that the manufacturer probably knew a thing or two, therefore, refer to the shop manual and see what they say?

    I was posing this same question as I undertook my (original bore size) 308 engine overhaul. Many feel the liners should be bored while in the block with a boring plate over them to mimic head installed torque. I personally felt the potential benifits of that were of little value at best, being that the liner is removable, and very stout, and that the loading from the head with such low torque could not reasonably distort the liner, which happens on cast iron American V-8's when the bore is part of the block.

    The second part that lead me away from this view, was that if I bought new liners from Ferrari, they would simply come in a box, and there would be no index marks or numbering to tell you which hole to put it in, and how it should be rotated. If in fact it was such a issue, this would be the case and you would order a new liner numbered to each hole with indexing marks.

    Now read the service manual. It explains that if the liner is to be bored, it is to be removed from the block. You already explained you have a 27 year old engine with some corrosion at the cylinder head to block interface. I am sure you want to make sure your liner seals are new, and the interface there is cleaned, yes? So for me, three strikes and the liners were coming out for boring.

    Regarding pistons, I chose Wiseco pistons that I ordered with higher compression, at I have less than $1000 into them with rings, pins, and clips. Boring cost me $25 per liner. YMMV

    To remove the liner? There are some tools, pullers, that you could use to remove them. I used a brass drift with a brass hammer and gently tapped them out from the bottom side. A couple didnt want to move at first, so it took some patience, but all is well.
     
  3. atlantaman

    atlantaman Formula 3

    Mar 31, 2002
    1,726
    Roswell, Georgia
    Full Name:
    Charles
    #3 atlantaman, Jun 7, 2005
    please remember that the liners on 308 cars are Nikosil lined and CAN NOT EVEN BE HONED WITHOUT HAVING TO HAVE THE NIKOSIL REAPPLIED.

    2 choices that I have seen---get NEW liners from Ferrari. Get nice new Iron liners made in USA with matching pistons to any size you want.


    Personally--I would ship the whole motor to TRutlands for an exchange rebuild and not deal with the dirty work.....
     
  4. Dave

    Dave F1 Rookie

    Apr 15, 2001
    2,722
    Little Rock
    Full Name:
    David Jones
    #4 Dave, Jun 7, 2005
    "please remember that the liners on 308 cars are Nikosil lined and CAN NOT EVEN BE HONED WITHOUT HAVING TO HAVE THE NIKOSIL REAPPLIED"

    That is true of the QV motors.
    But the older 2 valve motors do not have the Nikosil and can be bored and honed.
     
  5. tomoshea

    tomoshea Formula Junior

    Dec 29, 2003
    541
    Ireland
    Full Name:
    Tom O'Shea
    #5 tomoshea, Jun 7, 2005
    Charles

    The 2 V 1979 engines can be bored and honed, no Nikosil to worry about (thank God) it has its own issues.

    I am wondering has anyone bored the 2V's in place and if so what was the outcome, I accept all of the points made above though!

    Paul,

    When you indicated "a bit of patience" how long did it take to get the difficult ones out?, did yo have to heat the lock up and beat them out or something else.

    Overall how long do you think it took with a "good" liner to get it out without damaging it?

    As regards shipping to TRutlands - I am in Ireland, other side of the big pond, not an option really :)!
     
  6. Ferrari_tech

    Ferrari_tech Formula 3

    Jul 28, 2003
    1,527
    UK
    Full Name:
    Malcolm W
    #6 Ferrari_tech, Jun 7, 2005
    The maximum wear (on diameter) on the liners is 0.080mm - 0.100mm and the allowed ovalization and taper ratio is 0.010mm - 0.015mm. Ferrari donot really recommeng grinding "old liners", but if you choose to they recommend removing them. Removal is easy and a puller can be made in a couple of hours if you donot have access to the correct tooling.

    If worse comes to worse liners are still available from stock
     

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